Process of mordanting.



NITED STATES PATENT Erica.

ALOIDE FRANCOIS POIRRIER, OF PARIS, FRANCE.

PROCESS OF'MORDANTING.

SPECIFICATION forming part Of Letters Patent N 0. 646,760, dated April 3, 1900.

Application filed M y 1399- Serial No. 717,038. (No specimens.)

T0 aZZ whom it may concern:

Be it known that I, ALCIDE FRANCOIS POIR- RIER, a citizen of the Republic of France,residing at Paris, France, have invented Improvements in Processes of Mordanting, of which the following is a specification.

This invention relates to improved methods in the application of substantive sulfur coloring-matters to dyeing purposes, whereby the disadvantages to which the existing modes of application of such dyestuffs are subject are obviated.

In particular, the present improvements effect, first, a greater resistance of the dyed materials to the action of soap or of a wash of soap and carbonate of soda; secondly, a greater strength of the fiber after dyeing, steaming, &c., and, thirdly, a greater uniformity of the tints on cotton fabrics.

I have previously recommended as fixing agent for these coloring-matters a solution containing five per cent. of sulfate of copper and five per cent. of sulfuric acid or a solution containing five per centrof bichromate of potash and five per cent. of sulfuric acid, these percentages being calculated on the weight of the cotton to be dyed. In both cases there are obtained slightly-different tints-namely, greener in the case of sulfate of copper and bluer with bichromate of potash. In both cases the tints are very resisting to soap. When fixing by means of sulfate of copper and sulfuric acid, the tints obtained are sufficiently resistant to carbonate of soda of one per cent. or even of ten .per cent. strength as also to carbonate of soda and soap, (one per cent. and five per cent but the fiber is considerably affected by the steaming or when the fabrics after dyeing are exposed for some timein a hot and moist atmosphere. In the case of fixing I by means of bichromate and sulfuric acid the resistance to carbonate of soda is very weak and the fiber is also affected by the steaming.

Thus these two processes are subject to greater or less disadvantages, which are entirely obviated by the improved methods forming the subject of the present invention, whereby the tints are rendered very resistant to soap, quite resistant to boiling carbonate of soda, whether weak (one per cent.) or strong, (ten per cent.,) as also to a wash of carbonate of soda and soap, while the fiber thus treated does not appreciably lose strength during the steaming, whether with saturated or superheated steam. This result is obtained, first, by entirely doing away With the use of free sulfuric acid in either one or the other of the above processes; secondly, in the sulfate of copper process, substituting for the sulfate any other salt of copper-such as the chlorid acetate, &c.or any cupric c0n1bina tion-such, for instance, as the oxi'd of copper in ammoniacal solution; thirdly,in substituting in the bichromate process for the greater portion of the bichromate a salt 0 copper other than the sulfate.

The compositions of the fixing-baths would be, for example- Forinula N o. 1: Three per cent. chlorid of copper or the corresponding quantity of a cupric combination other than sulfate of copper. The cotton is maintained during from one-half to one hour at 90 centigrade.

Formula No. 2: Two to three per cent. of chlorid of copper and one to two per cent. of bichromate of potash. The cotton is maintained at from to centigrade during I 'from one-half to one hour.

The chlorid of copper can be very simply prepared by employing the corresponding quantity of commercial sulfate of copper in the presence of an excess of common salt.

The first formula is employed, by preference, for obtaining greenish tints and the second for obtaining bluish-black tints.

The diminution in the strength of the fiber, which, as already stated, is considerably less than with the previous processes, can be fur,-,

served with the existing methods are caused by the extreme oxidizability of the coloringmatter and are only produced when the fabric is subject to contact with the atmosphere while the dyeing process is being carried on. Dyeing in black is a process having two phases. In one the coloring agent is fixed on the fiber in a state of undetermined reduction. In the second phase after the washing of the fiber in order to eliminate what is mechanically retained the oxidation of the coloring agent transforms it (the coloring agent) into an intense black; but if in the first phase the wet fiber is allowed to remain in contact with the air that portion of the reduced coloring agent which impregnated the tissue without being fixed upon the same oxidizes very rapidly and becomes insoluble. The coloring agent thus oxidized is not fixed upon the fiber and may be removed by frictional contact. Hence the colorings thus obtained rub off and soil greatly white tissues with which they come in contact. It suffices,therefore, in order to avoid such defects to keep the fabric completely immersed during the whole of the dyeing process. The bath being of a reducing nature, the surface thereof constitutes a screen which protects the interior against all access of air and which consequently avoids all accidental local oxidation. The process should therefore be carried on in an ordinary fulling-machine, all the rollers of which are completely immersed in the bath. The surface of the latter will become slightly oxidized; but this will cause no inconvenience.

\Vhile in the following claims chlorid of copper is designated as the fixing agent or as forming apart of the fixing agent, its equivalents for the purpose stated, such as any salt of copper orcupric combination other than the sulfate of copper or the oxid of cop-.

action of a bath of chlorid of copper and bichromate of potash.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

AIIOIDE FRANCOIS POIRRIER.

Witnesses:

JULEs ARMENGAUD, .Ieunc, J. ALLISON BOWEN. 

